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A proteasome inhibitor reduces concurrent, sequential, and long-term IL-1 beta- and TNF-alpha-induced ECAM expression
Nilesh M Dagia1, Douglas J Goetz
1Department of Chemical Engineering, Ohio University, Athens, OH 45701, USA.
Abstract:
A promising approach for reducing aberrant leukocyte-endothelial adhesion during pathological inflammation is to inhibit endothelial cell adhesion molecule (ECAM) expression at the transcription level. Several compounds have been shown to decrease cytokine-induced upregulation of ECAMs primarily by modulating the activity of transcription factors [e.g., nuclear factor-kappa B (NF-kappa B)]. The majority of the in vitro studies have focused on the effect of transcription inhibitors on endothelial cells exposed to a single cytokine [primarily tumor necrosis factor-alpha (TNF-alpha)] for a relatively short period of time (primarily 4-6 h). However, in the in vivo setting, multiple cytokines [e.g., interleukin-1 beta (IL-1 beta) and TNF-alpha] may be present for extended periods of time. Thus we studied the effects of a transcription inhibitor, the proteasome inhibitor lactacystin, on ECAM expression and myeloid (HL60) cell adhesion to human umbilical vein endothelial cells (HUVEC) activated by concurrent, sequential, and long-term (24 h) treatment with IL-1 beta and TNF-alpha. We show, for the first time, that lactacystin inhibits 1) 4-h concurrent IL-1 beta- and TNF-alpha-induced expression of E-selectin, VCAM-1, ICAM-1, and HL60 cell adhesion to HUVEC; 2) 4-h TNF-alpha-induced expression of E-selectin, VCAM-1, and HL60 cell adhesion to HUVEC that have become desensitized to IL-1 beta activation; 3) 24-h TNF-alpha-induced expression of E-selectin and VCAM-1 but not ICAM-1; and 4) 24-h TNF-alpha-induced HL60 cell adhesion to HUVEC. Combined, our results demonstrate that a proteasome inhibitor can reduce concurrent, sequential, and long-term IL-1 beta- and TNF-alpha-induced ECAM expression and myeloid cell adhesion.
Insights
Proteasome inhibitor lactacystin reduces leukocyte-endothelial adhesion by decreasing endothelial cell adhesion molecule (ECAM) expression. This study shows lactacystin
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Aberrant leukocyte-endothelial adhesion contributes to pathological inflammation.
- Inhibiting endothelial cell adhesion molecule (ECAM) expression at the transcriptional level is a potential therapeutic strategy.
- Previous studies often used single cytokines and short exposure times, unlike in vivo conditions with multiple cytokines and prolonged exposure.
Purpose of the Study:
- To investigate the effect of the proteasome inhibitor lactacystin on ECAM expression and myeloid cell adhesion.
- To examine lactacystin's efficacy under conditions mimicking in vivo inflammation: concurrent, sequential, and long-term (24h) exposure to interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha).
- To assess lactacystin's impact on HL60 cell adhesion to human umbilical vein endothelial cells (HUVEC).
Main Methods:
- Human umbilical vein endothelial cells (HUVEC) were treated with IL-1 beta and TNF-alpha concurrently, sequentially, and over 24 hours.
- Cells were co-treated with the proteasome inhibitor lactacystin.
- Expression of E-selectin, VCAM-1, and ICAM-1 was measured, along with HL60 cell adhesion to HUVEC.
Main Results:
- Lactacystin inhibited ECAM expression (E-selectin, VCAM-1, ICAM-1) and HL60 cell adhesion after 4-hour concurrent IL-1 beta and TNF-alpha treatment.
- Lactacystin reduced ECAM expression and cell adhesion when HUVEC were pre-desensitized to IL-1 beta and then treated with TNF-alpha.
- Lactacystin inhibited 24-hour TNF-alpha-induced E-selectin and VCAM-1 expression, and HL60 cell adhesion, but not ICAM-1.
Conclusions:
- Proteasome inhibitor lactacystin effectively reduces ECAM expression and myeloid cell adhesion under various inflammatory conditions.
- Lactacystin demonstrates efficacy against concurrent, sequential, and long-term cytokine-induced inflammation, suggesting therapeutic potential.
- The findings highlight the role of proteasome inhibition in modulating complex inflammatory responses involving multiple cytokines.